Novellus Systems (Nasdaq: NVLS) announced today that it has
developed conformal film deposition (CFD™) technology for
depositing 100 percent step coverage dielectric films on structures
with aspect ratios of up to 4:1.
The innovative CFD technology addresses sub-32nm requirements
for front-end-of-line (FEOL) applications such as gate liners and
spacers, shallow trench isolation high-k metal gate (HKMG) liners,
and spacers used for double patterning applications.
Novellus' CFD oxide films possess quality and composition
comparable to thermal oxide films, including low leakage, high
break-down voltage, and low wet etch rate.
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| Figure shows the 100 percent step coverage of a
CFD film over a photoresist structure with no loading effect on the
underlying resist. |
Variability in sub-32 nm transistor dimensions is a key area of
industry focus due to the impact on device performance. New,
highly conformal spacer films have been developed to control these
critical dimensions across the wafer. While integrated
metrology and advanced process control techniques can minimize
wafer-to-wafer and lot-to-lot variability in spacer dimensions,
within-wafer variability is controlled by the technology used to
deposit the spacer film. Moreover, the dielectric layers used
for these spacer films need to be deposited at temperatures that
are low enough to minimize dopant diffusion.
Novellus has developed CFD technology that deposits highly
conformal films for FEOL applications that meet the quality and low
temperature requirements of sub-32nm devices. Figure 1A shows
the 100 percent conformality of CFD oxide films deposited on FEOL
structures with increasing aspect ratios. The FTIR spectrum
in Figure 1B shows the strong similarity between a CFD oxide film
deposited at 400°C and a furnace-grown thermal oxide. The
current-voltage inset plot shows the high breakdown performance
behavior of the CFD film. Furthermore, analysis has shown
that the film quality on the sidewall matches that in the
field. In comparison to competitive spacer films deposited
using an atomic layer deposition process, the combination of
Novellus' CFD technology and VECTOR's multi-station sequential
deposition (MSSD) architecture delivers superior within-wafer and
wafer-to-wafer repeatability, with significantly higher throughput
and lower chemical consumption.
With the delay in Extreme UV (EUV) lithography, the
semiconductor industry is turning to spacer-based double patterning
schemes for sub-3X nm memory and sub-2X nm logic devices. The
most cost-effective double patterning schemes utilize a photoresist
core followed by a spacer film with 100 percent step
coverage. The spacer films have to be deposited using
temperatures and chemistries that are compatible with photoresist
materials. Spacer films used in a double patterning scheme
need to demonstrate excellent conformality with no loading effects
that cause line "bending," and yet deliver outstanding within-wafer
patterning uniformity.
Novellus' innovative CFD films can be deposited at substrate
temperatures less than 50°C, and are therefore compatible with
advanced photoresists used in double patterning schemes.
Figure 2A shows the 100 percent step coverage of a CFD film over a
photoresist structure with no loading effect on the underlying
resist. Figure 2B shows that the thickness range of the CFD
film is less than 0.2 percent, which translates to less than one
angstrom on a typical 300 angstrom thick film, a requirement for
advanced patterning at 32nm and beyond.
"CFD technology offers a breakthrough in the deposition of low
temperature dielectric films with quality equivalent to a furnace
deposition," said Kevin Jennings, senior vice president of
Novellus' PECVD Business unit. "As device dimensions shrink
beyond 32nm, films deposited using CFD technology will be required
for multiple applications. The ability to deposit these films
on the reliable, production-proven VECTOR platform ensures superior
within-wafer and wafer-to-wafer repeatability, with significantly
higher throughput and lower chemical costs."
Source: http://www.novellustechnews.com/
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